Collaborating Producer: Garth Shaw, Fairview
Research Coordinator: Dr. Akim Omokanye
Cattle can be used to introduce legumes into pastures. The method is an inexpensive renovation technique that can be used to improve pastures over a 3 to 4 year period. Livestock seeding works because "hard seeds" found in legume seed lots pass through the animal's digestive tract and remain viable. However, quick germinating seeds are killed. Reports have shown that it takes 24-72 hrs for the seed to travel through the digestive tract. The seed will not germinate in freshly excreted feces. The feces must break down first and be thinly distributed on the soil. Sward composition is an important consideration when deciding on the types of forage mixture and the seeding rates. The objective of the present study is to assess livestock seeding of Anik alfalfa—cicer milkvetch mix in pasture rejuvenation.
Methods:
The site is located in Fairview at Garth Shaw’s farm. A 50 acre pasture paddock is being used for the study. The site consisted of mainly bromegrass and alfalfa. Before any grazing started, plant composition through plant sampling method with a 0.5m x 0.5m quadrat was carried out. For the plant composition, different forage species present were identified and their dry weights determined. This will enable us to assess any improvements in the paddock in 2013 and thereafter. There were 3 treatments (see Figure 1 below): 1) broadcast of Anik alfalfa-cicer milkvetch mix (1 acre), 2) livestock seeding of Anik alfalfa-cicer milkvetch mix (48 acres) and 3) check - no seeding (1 acre). Seeding rate for the mix was 2.3 lb/acre of Anik alfalfa + 3.4 lb/ acre cicer milkvetch. The study commenced on June 20, 2012 with broadcast seeding. Grazing of the entire paddock started 2 days later. Assessments of the site will continue for 2 to 3 years.
The site was marked out and electric fence was used for the border between livestock seeding and broadcast/ check sections. Figure 1 shows the plot layout and the order of grazing. For the broadcast section, an ATV mounted spreader was used to broadcast the seeds at a speed of 9 MPH (Picture 1). The ATV mounted spreader covered about 25 feet in width per pass. After broadcasting the legume mix, the site was grazed by cows to create animal impact on the broadcast seeds.
For the livestock seeding section, minerals were mixed with the legumes seeds and the mixtures (seeds & minerals) were randomly placed across the entire livestock seeding section (48 acres), to allow better distribution of the legumes seeds across the paddock. Prior to grazing, the animals were starved of minerals for a few days so as create a crave for minerals at the time of grazing.
For the check section of the paddock, no seeding (broadcast or livestock seeding) was carried out but cows were allowed to graze the section at the same time as they did on the broadcast treatment section.
Collection of Feces and Seed Recovery
Samples of feces were collected from the livestock seeding treatment section. The collection started 48 hrs after the cows started grazing and continued every other day for a total of 5 sampling times. On each sampling day, about 2.5 kilograms of fresh feces were collected at random and weighed in the laboratory within 1 hour of collection. Three 300 grams (900 grams in total) were weighed out of the collected fresh feces samples. The samples were washed through a running tap water and sieved to recover any legume seeds. After washing, the samples were spread out on paper towel and air dried for about 1 hour in the laboratory. Legume seeds (Anik and cicer milkvetch) were identified, sorted and counted separately.
Germination Testing
A seed germination test was carried out in the laboratory using the moist paper towel method. The paper towels were placed on aluminium foil trays and moistened once everyday before 9am. Seeds that were removed from washed feces (300 grams field sampled feces x 3 samples/replicates) were used for the germination tests. Two checks (Anik alfalfa and cicer milkvetch) were included at the start of the germination test. For the checks, 100 seeds were counted per replicate. Germinated seeds were counted and removed daily when the radicle was clearly visible. The germination test lasted for about 4 weeks, after which the number of seedlings in each replicated sample was interpreted as falling into one of the following categories: germinated, hard and dead seeds. Ungerminated seeds were tested for viability on termination of the test by either squeezing the seeds with a blunt-nosed thumb forceps in half to inspect the embryo (with a magnifying lens). Dead seeds would normally rot or have brown embryos. Seeds with coats that do not freely allow the passage of either water or oxygen are termed hard seeds.
Results
Fecal Seed Recovery
During sampling, seed recovery from 300 grams of fresh faeces was 51 seeds for Anik alfalfa and 56 seeds for cicer milkvetch (Table 1). But the mean percentage dead seed was lower for cicer milkvetch (15% dead seeds from 300 grams fresh feces) than Anik alfalfa (20% dead seeds from 300 gram fresh feces) (Table 1).
Seed Germination
Overall, seed germination from 300vgrams fresh feces was slightly higher for Anik alfalfa (65.0%) than cicer milkvetch (59.6%) (Table 1). Comparing the germinated seeds from sampled feces to those of checks, for Anik alfalfa, there appeared to be more germinated seeds from check (71%) than from those seeds that passed through the cows (65%). But for cicer milkvetch, the reverse was the case as cicer seeds slightly appeared to have been favoured by the cows digestive tract (52% for check vs 60% for seeds that passed through the cows).
Regardless of whether the legume seeds passed through the cows digestive tract or not, the percentage hard seeds appeared to be generally higher for cicer milkvetch than Anik alfalfa (Table 1). Even for cicer milkvetch, the check had more hard seeds (45%) than the seeds that passed through the cows (29%).
Generally, there were more dead seeds from the legume seeds that passed through the cows digestive tract than those used for checks. Interestingly, Anik alfalfa had far more dead (or damaged seeds) in the cows’ feces (10.%) than from the check (0.5) (Table 1).
Future Plans: In 2013, the site will be assessed for seedling emergence and general growth performance before any grazing takes place. This will be followed by an update through a full written report on the project and the impacts of using livestock to seed legumes for pasture rejuvenation in this environment.